The invention relates to a turbo charger arrangement for an internal combustion engine with a system control valve for operating a motor connected to a waste gate for controlling the engine exhaust gas pressure separately from an air return valve for returning compressed air through a short circuit line from the charger discharge side to the charger inlet side.
FIG. 1 shows schematically a turbocharger control arrangement of Bosch for a turbocharged engine wherein a system control valve for controlling the operating motor for an exhaust gas waste gate is arranged separately from an air return circuit. The system control valve includes a first control line extending from the air intake pipe at the suction side of the charger to the system control valve includes a first control line extending from the air intake pipe at the suction side of the charger to the system control valve. A second control line extends from the system control valve to the discharge side of the charger and a third control line extends from the system control valve to the operating motor for actuating the waste gate.
In a first control position of the system control valve, the operating motor of the waste gate is in direct communication with the suction side of the charger. In a second control position, the discharge side of the charger is in communication with the operating motor of the waste gate. When the engine is driven by the vehicle, the air return valve is opened whereby air discharged from the charger is returned to the charger inlet side. The air return valve is controllable by way of a separate control line.
Such an arrangement for controlling turbocharged engines under the various operating conditions has the disadvantage that it requires a large number of components and an extensive connecting line arrangement for the interconnection of the components.
It is the object of the present invention to provide a simple and relatively inexpensive turbocharger control arrangement for operating a turbocharged internal combustion engine under various operating conditions.